多重网格扩散综合加速的三维离散纵标中子输运程序SN3C

为提高已开发三维中子输运数值计算程序SN3C的效率,本文采用一致的扩散综合加速方法加速源迭代,并用Chebyshev加速方法提高幂迭代的收敛速度.针对扩散综合加速方法中求解扩散方程的特点,发展了基于完全多重网格方法的求解技术,数值试验的结果显示,SN3C的计算结果与Monte Carlo方法以及EVENT的计算结果符合很好;并且,对于中小规模的问题,完全多重网格方法的效率可与具有最优松弛因子的块超松弛方法相比;对于较大规模的问题,完全多重网格方法的性能更好.     

一维波动方程反演波阻抗的实现及效果

利用波动方程反演波阻抗，由于计算工作量大、稳定性差等原因，一直没有在地震勘探资料处理中得到实际应用。本文提出的一维波方程逐段折叠反演方法能较好地克服上述缺陷，具有计算量相对较小、精度高、稳定性好等特点。并在大庆长垣东部和西部的实际资料处理中见到了良好的效果。     

反偏移法三维波动方程正演

三维地震资料的处理与解释往往都需要三维正演模型给予验证，以得到准确的处理、解释结果。本文提出的三维正演方法是一种偏移算法的逆运算方法－有限差分反偏移法。这一算法具有算法简单、运算量小及深度方向分辨率高的特点，是一种快速、高精度的正演算法。反偏移法虽是偏移算法的逆运算法，却出现常规偏移算法中所没有的很多问题。为此，本文进行了三种不同反偏移方法试验，并采用了一种新的浮动坐标变换，使正演结果精度得到很大     

机械研磨 Ni_(50)B_(50)合金形成非晶的过程

本文研究了机械研磨 Ni_(50)B_(50)合金非晶的形成过程。唯象地提出用 J-M-A 方程描述此过程,并作了简单的讨论。     

OPERATOR-SPLITTING METHOD FOR ANALYSIS OF CAVITATION IN LIQUID-LUBRICATED HERRINGBONE GROOVED JOURNAL BEARING

ＮＯＭＥＮＣＬＡＴＵＲＥｃ　ｒａｄｉａｌｃｌｅａｒａｎｃｅｈ　ｆｉｌｍｔｈｉｃｋｎｅｓｓ ｈ　ｄｉｍｅｎｓｉｏｎｌｅｓｓｆｉｌｍｔｈｉｃｋｎｅｓｓ (ｈ/ｃ)Ｌ/Ｄ　ｒａｔｉｏｏｆｌｅｎｇｔｈｔｏｄｉａｍｅｔｅｒｐ　ｆｉｌｍ ｐｒｅｓｓｕｒｅｅ　ｅｃｃｅｎｔｒｉ     

地震和测井联合反演储层波阻抗技术

通过地震和测井联合反演，可以获得高分辨率的井间地层波阻抗分布的信息。综合应用波动方程反演和神经网络分析来反演地层波阻抗参数，其过程分3步：第一步，应用先验地质知识，对地震数据和测井曲线进行地质解释，并对油井曲线进行对层和标定，然后求取相应的层速度的低频信息，旨在搞清井间地层结构状况，为线性反演提供地层产状的先验信息；第二步，应用非线性波动方程反演，在层速度界面及井中物性参数约束下，从地震数据中反演高分辨率的反射系数及波阻抗参数；第三步，应用CUSI神经网络分析方法，以高分辨率的反射系数及波阻抗等参数作为约束，以沿层求取的地震特征作为输入，以井中反演的波阻抗参数为期望输出，对非线性波动方程反演出的波阻抗参数进行非线性标定，得出井间的地层绝对波阻抗物性参数。     

GENERATION OF NONLINEAR INTERNAL WAVES ON CONTINENTAL SHELF

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｅｒｎａｌｔｉｄａｌｉｎｔｅｒａｃｔｉｏｎｗｉｔｈｂｏｔｔｏｍｆｅａｔｕｒｅｓａｐｐｅａｒｓｔｏｂｅｔｈｅｄｏｍｉｎａｎｔｍｅｃｈａｎｉｓｍｆｏｒｇｅｎｅｒａ ｔｉｏｎｏｆｔｈｅｃｏｈｅｒｅｎｔｏｃｅａｎｉｃｉｎｔｅｒｎａｌｗａｖｅｓｔｈａｔａｒｅｏｂｓｅｒｖａｂｌｅｗｉｔｈＳＡＲ ,ｃｌｏｓｅｒｔｏｓｈｏｒｅ ,ｒｉｖｅｒｉｎｅｏｒｇｌａｃｉａｌｉｎｔｒｕｓｉｏｎａｎｄｃｏｎｔｉｎｅｎｔａｌｂｒｅａｋｐｒｏｖｉｄｅｓｅｃ ｏｎｄａｒｙｇｅｎｅｒａｔｉｎｇｍｅｃｈａ…     

毫米波谐波振荡器的Volterra级数分析法

本文基于Ｖｏｌｔｅｒｒａ级数法和非线性转移函数理论，提出了一种分析毫米波谐波振荡器的新方法，给出了描述其非线性特性的决定方程，通过求解一组非线性代数方程，便可计算出谐波振荡器的振荡频率和幅度。文中给出了具体分析实例，并与谐波平衡法等进行了比较，结果表明：这种方法具有理论严密、准确性高、适用范围广等特点，特别是利用一次决定方程的结果作为其它非线性数值分析方法的初始估值，则可大大地节约计算时间，并容易     

Adhesive Contact of a Membrane with a Hemispherical Indenter: Theoretical Analysis and Model Liquid System

The axisymmetric Laplace equation is solved numerically to extract contact-angle data for a flat liquid/vapor interface contacting a submerged hemispherical solid. The liquid/vapor interface is treated as a membrane, with a membrane tension equal to the surface energy of the liquid. By measuring the vertical displacement of the membrane and the projected contact area the membrane makes with the hemisphere, the contact angle and correspondingly the driving force for motion of the contact line can be measured. We show that characteristic receding and advancing contact angles can be obtained by measuring the contact radii formed upon initial contact between the interface and hemisphere and final contact just prior to detachment of the interface, respectively. Use of the technique is illustrated with a model experiment involving the contact of an air/water interface with a poly(methyl methacrylate) surface.     

Non‐reflecting artificial boundaries for transient scalar wave propagation in a two‐dimensional infinite homogeneous layer

This paper presents an exact non‐reflecting boundary condition for dealing with transient scalar wave propagation problems in a two‐dimensional infinite homogeneous layer. In order to model the complicated geometry and material properties in the near field, two vertical artificial boundaries are considered in the infinite layer so as to truncate the infinite domain into a finite domain. This treatment requires the appropriate boundary conditions, which are often referred to as the artificial boundary conditions, to be applied on the truncated boundaries. Since the infinite extension direction is different for these two truncated vertical boundaries, namely one extends toward x →∞ and another extends toward x→‐ ∞, the non‐reflecting boundary condition needs to be derived on these two boundaries. Applying the variable separation method to the wave equation results in a reduction in spatial variables by one. The reduced wave equation, which is a time‐dependent partial differential equation with only one spatial variable, can be further changed into a linear first‐order ordinary differential equation by using both the operator splitting method and the modal radiation function concept simultaneously. As a result, the non‐reflecting artificial boundary condition can be obtained by solving the ordinary differential equation whose stability is ensured. Some numerical examples have demonstrated that the non‐reflecting boundary condition is of high accuracy in dealing with scalar wave propagation problems in infinite and semi‐infinite media. Copyright © 2003 John Wiley & Sons, Ltd.